DataFrame.groupby
Group DataFrame using a mapper or by a Series of columns.
danfo.DataFrame.groupby(columns)
Parameters
Type
Description
Default
columns
Array
The names of a column(s) in the DataFrame to group by
Examples
Groupby a single column from a DataFrame
Node
Browser
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const dfd = require("danfojs-node")
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let data = [["Pear", 2, 3], ["Pear", 5, 6], ["Apple", 30, 40], ["Apple", 89, 78]]
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let cols = ["A", "B", "C"]
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let df = new dfd.DataFrame(data, { columns: cols })
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let group_df = df.groupby(["A"])
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console.log(group_df)
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// ouput
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Groupby {
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colDict: {
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Pear: { A: [Array], B: [Array], C: [Array] },
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Apple: { A: [Array], B: [Array], C: [Array] }
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},
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keyToValue: { Pear: [ 'Pear' ], Apple: [ 'Apple' ] },
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keyCol: [ 'A' ],
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data: [
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[ 'Pear', 2, 3 ],
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[ 'Pear', 5, 6 ],
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[ 'Apple', 30, 40 ],
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[ 'Apple', 89, 78 ]
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],
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columnName: [ 'A', 'B', 'C' ],
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colDtype: [ 'string' ],
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colIndex: [ 0 ]
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}
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A groupby operation will return a GroupBy class object. You can apply any of the following operation on the groupby result:
Example of Groupby and apply a sum function
Node
1
const dfd = require("danfojs-node")
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let data = [["Pear", 2, 3], ["Pear", 5, 6], ["Apple", 30, 40], ["Apple", 89, 78]]
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let cols = ["A", "B", "C"]
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let df = new dfd.DataFrame(data, { columns: cols })
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let group_df = df.groupby(["A"]).sum()
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group_df.print()
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╔════════════╤═══════════════════╤═══════════════════╤═══════════════════╗
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║ │ A │ B_sum │ C_sum ║
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╟────────────┼───────────────────┼───────────────────┼───────────────────╢
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║ 0 │ Pear │ 7 │ 9 ║
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╟────────────┼───────────────────┼───────────────────┼───────────────────╢
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║ 1 │ Apple │ 119 │ 118 ║
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╚════════════╧═══════════════════╧═══════════════════╧═══════════════════╝
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Groupby a two columns from a DataFrame
Node
Browser
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const dfd = require("danfojs-node")
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let data = [["Pear", 2, 3], ["Pear", 2, 6], ["Apple", 30, 40], ["Apple", 89, 78]]
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let cols = ["A", "B", "C"]
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let df = new dfd.DataFrame(data, { columns: cols })
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let group_df = df.groupby(["A", "B"]).sum()
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group_df.print()
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╔════════════╤═══════════════════╤═══════════════════╤═══════════════════╗
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║ │ A │ B │ C_sum ║
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╟────────────┼───────────────────┼───────────────────┼───────────────────╢
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║ 0 │ Pear │ 2 │ 9 ║
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╟────────────┼───────────────────┼───────────────────┼───────────────────╢
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║ 1 │ Apple │ 30 │ 40 ║
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╟────────────┼───────────────────┼───────────────────┼───────────────────╢
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║ 2 │ Apple │ 89 │ 78 ║
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╚════════════╧═══════════════════╧═══════════════════╧═══════════════════╝
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Last modified 5mo ago